1. Field of the Invention
The present invention relates to a miniature linear guide apparatus which is light, compact, highly accurate, and useful as a driving device for a hard disk, a floppy disk, or a memory (CD-ROM) device utilizing a compact disk, and in particular, relates to an improvement in the attaching structure of a member to be driven to ensure high accuracy.
2. Description of the Relevant Art
A miniature linear guide apparatus of this type is shown, for example, in FIGS. 6 and 7.
In this apparatus, a slider 52 is assembled, for longitudinal movement, to a guide rail 51 having a U-shaped cross section. The slider 52 is formed integrally by fitting a cap 54 having a flat plate shape and a circulator 56 having ball circulating paths 55 into a recess of a race member 53 having an inverted U-shaped cross section.
The race member 53 has longitudinally extending ball rolling grooves 53B formed in both side surfaces, and the guide rail 51 has similar ball rolling grooves 51B formed in both inner surfaces of its side walls respectively opposing the ball rolling grooves 53B of the race member 53. Steel balls B are inserted in the paths formed by opposing ball rolling grooves 51B and 53B. These balls B circulate infinitely through the ball circulating paths 55 formed in the circulator 56, thereby allowing the slider 52 to move linearly. The race member 53 of the slider 52 has screw holes 57 formed in its flat portion, and a member to be driven (not shown) can be attached directly to the race the race member 53 by screws.
However, the miniature linear guide apparatus involves a problem in that when a member to be driven is attached to the race member 53 of the slider 52, the screws inserted through the screw holes 57 must be clamped. Conseqently, the race member 53 which is made of a thin steel plate is deformed, and as a result, the clearance between the outer surface of the race member 53 and the inner surface of the guide rail 51, and an opposing positional relationship between the race member 53 and the guide member 51 are changed. Consequently, dimensional tolerances of the ball rolling grooves 53B, and movement accuracy and positional accuracy of the slider 52 deteriorate proving it difficult to achieve a miniature linear guide with high accuracy.
Furthermore, when the member to be driven is fixed by screws, the depth of clamping is dependent on the plate thickness of the race member 53, and the interference area available for clamping is decreased as the plate thickness is decreased. Thus, it becomes difficult to make the apparatus small in size and light in weight.